This invention relates to an intake apparatus for a two cycle engine and more particularly to an improved rotary valve and induction system for an engine of the two cycle type.
The advantages of two cycle crankcase compression internal combustion engines are well known. One of the main advantages of this type of engine is the simplicity of the engine. Frequently these engines are operated with nothing more than a reed type check valve into the crankcase chamber and a porting arrangement that accommodates the transfer of the charge from the crankcase chamber to the combustion chamber of the engine. However, it has been recognized that performance may be improved, in some instances, through the use of some form of valve that rotates in unison with the crankshaft and which controls the opening and closing of a port that communicates the induction system with the crankcase chamber or the combustion chamber.
A wide variety of fixed type valve mechanisms have been proposed for this purpose. However, it has been acknowledged that the performance of the engine can be improved by employing a variable valve timing for such valves. The type of variable valve timing mechanism previously incorporated have utilized a pair of blade type rotating valve plates that move relative to each other to change the timing events. These types of device both retard the point at which the port opens and advance the time at which the port closes. However, it may not always be desirable to provide such extreme changes in both directions of port operation. Furthermore, the prior art type of arrangements have employed centrifugal governors for their operation and hence absorb power from the engine in order to achieve the valve operation and the change in timing.
It is, therefore, a principal object of this invention to provide an improved porting arrangement for a two cycle engine and valve control for the port.
It is a further object of this invention to provide an improved and simplified valve port timing arrangement for the rotary valve of a two cycle engine.
It is a further object of this invention to provide a valve port timing arrangement for the rotary valve of a two cycle engine wherein the timing adjustment is made without requiring power from the engine.
One common application for two cycle engines is in motor cycles. In conjunction with motorcycle applications, if a rotary valve is employed it is the normal practice to induct the charge into the crankcase at one side of the crankcase. With the normal disposition of the engine in the motorcycle, this places the induction system at the side of the motorcycle. The disadvantage with such side placement is that the induction system may interfere with the amount at which the motorcycle can be leaned by the rider when cornering.
It is, therefore, a still further object of this invention to provide an improved induction system for a two cycle engine as employed in a motorcycle wherein the induction system does not interfere with the amount of leaning possible for the motorcycle.
It is a further object of this invention to provide an improved and simplified induction system and fuel injection system with cooperating throttle valve arrangement for a two cycle engine utilized to power a motorcycle which will be compact and yet easy to service.